Click Image to Enlarge
Advancements in hydraulic presses and servo robots were unveiled by Arburg GmbH at its annual Technology Days conference and technical exhibition in March at its headquarters in Lossburg, Germany. A number of "guest" firms also made presentations at the event. They unveiled in-mold labeling (IML) technology from a relatively unknown source and a new gas-assist technique that promises super-fast cycles.
Arburg rolled out the newest model in its Allrounder Universal (U) line of small hydraulic presses. The new Allrounder 370 U is the largest in the series, with tiebar spacing of 370 x 370 mm and clamping choices of 49.5, 66, and 77 tons. The U line now has three models starting at 14 tons.
Arburg also showed a new all-servo version of its Multilift V robot that can move at speeds up to 4000 mm/sec on its main axis. The air-cooled robot can handle payloads from 22 to 44 lb and is said to require less overhead space than competing models.
A new gas-assist method is said to cool parts faster than conventional gas assist and even water injection. The patented Gas Injection Molding-Cooling (GIM-Cool) process is a full-shot method that uses an overflow well at the end of fill and two special gas nozzles at opposite ends of the part.
In the first stage of the process, a full-shot of material is injected. Then one nitrogen gas valve is opened, allowing gas into the part, while the overflow valve on the opposite end of the part is opened to receive melt displaced by the gas. When the part is completely cored out, the overflow gate is closed and the second gas pin opens near the overflow gate. Gas flows continuously through the al ready hollow part and exits through the first gas pin. This reportedly en hances cooling and gives a smoother inner part surface.
The system was developed jointly by Huf Tools GmbH, Maximator GmbH, and also Linde AG. Maximator developed the special gas-flow switch over device and valve-gate nozzle. Linde supplies nitrogen gas and a full range of GIM-Cool technical services. The overflow-well concept is licensed from Gain Technologies.
Huf Tools built the mold and is using GIM-Cool itself to produce door handles for the Ford Focus car. The 30% glass-filled nylon handles weigh 165 g. In a four-cavity tool, GIM-Cool reduced overall cycle time to 32 sec from 68 sec with standard single-nozzle gas assist. It even beat the 42-sec cycle obtained with water injection, says Michael Lehmann, technical director. Huf Tools is building GIM-Cool molds for Ford Focus door hand les for molders in Poland, Spain, Wisconsin and Tennessee.
A German producer of molds and of IML automation systems for food packaging, pharmaceutical, and medical applications was another guest of Arburg at the Technology Days. SysTec Komplettsysteme (which has a U.S. office) offers IML tooling and automation for two-face stack molds with up to 8 + 8 cavities. SysTec has designed IML systems for parts up to 3 liters. Its servo-driven systems place labels with accuracy to ±0.2 mm. Vacuum sensors on the dummy core, handling device, and mold cavity verify label placement in all cavities.